An investigation was made of the effects of lightly Si doping upon the minority carrier diffusion length in n-type GaN films by analyzing photovoltaic spectra and positron annihilation measurements. It was found that the minority carrier diffusion length in undoped n-type GaN was much longer than that in lightly Si-doped GaN. Positron annihilation analysis demonstrated that the concentration of Ga vacancies was much higher in lightly Si-doped GaN and suggested that Ga vacancies, rather than dislocations, were responsible for the shorter minority carrier diffusion lengths in the investigated Si-doped GaN samples, due to the effects of deep-level defects.

Effect of Light Si Doping on the Minority Carrier Diffusion Length in n-Type GaN Films. D.G.Zhao, D.S.Jiang, H.Yang, J.J.Zhu, Z.S.Liu, S.M.Zhang, J.W.Liang, X.P.Hao, L.Wei, X.Li, X.Y.Li, H.M.Gong: Applied Physics Letters, 2006, 88[25], 252101 (3pp)